Fluxmail and EmailEngine both connect existing mailboxes through self-hosted MCP and REST APIs, and Fluxmail is also available hosted as Fluxmail Cloud. Self-hosted Fluxmail includes local stdio, a CLI, and a free Personal plan. EmailEngine adds inbound webhooks, queues, and mail merge; its native MCP endpoint is in beta.
This comparison covers Fluxmail Cloud, which we host, and self-hosted Fluxmail, which you run. Cloud doesn’t keep a copy of your mail.
Which self-hosted email API should an AI agent use?
For an agent that works in your own Gmail, Outlook, or IMAP mailbox over MCP, use Fluxmail. For a backend that reacts to each incoming message, use EmailEngine. Both run on your own server and keep provider credentials there.
Neither one creates a new inbox for an agent. If the agent needs an address of its own, compare Fluxmail with AgentMail instead.
Choose Fluxmail for local stdio clients, a CLI that shares the email API, a small deployment with SQLite and an ongoing free plan, or a hosted option through Fluxmail Cloud. Choose EmailEngine when inbound webhooks, queues, templates, or mail merge are central to your application. Both support MCP clients and scoped mailbox access.
Feature comparison
Feature
Fluxmail
EmailEngine
Architecture
Deployment
Local process or Docker
Or hosted in Fluxmail Cloud
Self-hosted server
Local, cloud, on-premises, or Docker
Runtime
Node.js 22.22+ or Docker
Packaged builds or Node.js 20+
Docs suggest 2 GB of memory to evaluate, 4 to 8 GB for production
Primary interface
MCP, REST API, and CLI
REST API, webhooks, and MCP (beta)
Native MCP server
Yes
stdio and Streamable HTTP; hosted with OAuth in Cloud
Yes, in beta
Since version 2.79.2 in August 2026; disabled until an administrator enables it
Storage dependency
SQLite
Self-hosted; stored on the Fluxmail machine
Redis
Redis 6.2 or later, or a Redis-compatible service
Real-time webhooks
Not a core interface
Yes
Account and message events with delivery controls
Providers and email work
Provider APIs
Gmail API and Microsoft Graph
Gmail API and Microsoft Graph
Generic mailboxes
IMAP and SMTP
IMAP and SMTP
Search, read, and attachments
Yes
Yes
Draft, send, and organize
Yes
Yes
Scheduling and queues
Scheduled send and status tools
Scheduled sending is self-hosted only
Outbox queues, retries, and scheduled send
Templates and mail merge
Not built in
Built in
Access and licensing
Agent permissions
Read-only, read-write, full, or custom
Plus member and mailbox scope
MCP scopes, permission narrowing, and account binding
Tool discovery respects the calling credential
Credential encryption
Built-in encryption for provider credentials
Requires EENGINE_SECRET in production
Credentials are not encrypted without it
License
Elastic License 2.0
Source-available
Commercial subscription
Pricing
Free self-hosted plan; Pro $15/month; Business $25/member/month
Same Pro and Business prices in Cloud and self-hosted. Annual: Pro $120; Business $240/member
$1,450/year after a 14-day trial
Unlimited instances and IMAP accounts; VAT excluded
A closer look
Both products connect AI agents to existing mailboxes
EmailEngine ships a native MCP endpoint in beta. It supports reading, organizing, drafting, and sending, and an administrator must enable it. MCP calls use the same authorization as the REST API.
Fluxmail includes a native MCP server with email-specific tools and schemas designed for model use. Self-hosted Fluxmail serves MCP, REST, and a CLI from one deployment, so agents, applications, and operators can share one email service. Fluxmail Cloud serves MCP and REST.
Choose the permissions each agent needs
Fluxmail can expose only the tools a client is allowed to use. A research agent can be read-only, an organizer can manage messages without sending, and a drafting agent can work with drafts without permanent deletion. Member access and mailbox allowlists apply separately on every request.
EmailEngine also filters tool discovery by credential, supports permission narrowing and account binding, and separates mail access from instance-management tools. Compare the exact operations each profile allows before connecting an agent.
Self-hosted Fluxmail installs from npm or Docker
Install the fluxmail npm package and run "fluxmail setup", then add Gmail with "fluxmail accounts add gmail". Local Gmail setups use the bundled Google app, so you do not need a Google Cloud project. Outlook needs your own Microsoft Entra app registration. For a shared server, run the published Docker image behind an HTTPS proxy.
Agents connect over stdio on the same computer, or over Streamable HTTP with OAuth or an API key. Claude Code and Cursor can launch Fluxmail over stdio. ChatGPT and Claude on the web connect from their own servers, so they need a Fluxmail server with a public HTTPS URL.
Fluxmail needs no Redis, and self-hosting is free for small setups
Self-hosted Fluxmail stores its database in SQLite, so it does not require a separate Redis instance. Its Personal plan remains free for one member and three mailboxes. With Fluxmail Cloud there is no server to run, and a workspace's first subscription starts with a seven-day trial.
EmailEngine requires Redis and provides a fourteen-day trial before its paid production license. Fluxmail is a smaller starting point for personal agents and teams that do not need EmailEngine's additional application infrastructure.
Which should you choose?
Best choice
Fluxmail
AI agents are the primary users of the email connection.
You want MCP, REST, and CLI from the same server.
Each client needs its own actions and mailbox allowlist.
A small personal deployment should remain free after evaluation.
You prefer a smaller service with SQLite and no Redis dependency.
EmailEngine
Your application is built around inbound webhooks and event processing.
You need templates, mail merge, SMTP proxying, or detailed outbox queues.
You want unlimited accounts and instances for a flat annual price.
Common questions
Is Fluxmail an EmailEngine alternative?
Yes, for connecting existing mailboxes through a self-hosted service. Fluxmail is an option for MCP and REST applications that need local stdio, CLI access, or an ongoing free plan with SQLite storage. EmailEngine is the closer fit for webhook-heavy backends, queues, templates, and mail merge.
Which self-hosted email API works with Gmail and Outlook?
Both do. Fluxmail and EmailEngine connect Gmail through the Gmail API, Outlook through Microsoft Graph, and other providers through IMAP and SMTP. Mail stays with your provider.
Does EmailEngine support MCP?
Yes. EmailEngine has a native MCP server in beta, disabled by default until an administrator enables it. Fluxmail supports local stdio and Streamable HTTP, and Fluxmail Cloud hosts an MCP server with OAuth sign-in.
Which one is free?
Self-hosted Fluxmail has an ongoing free Personal plan for one member and three mailboxes, and Fluxmail Cloud starts with a seven-day trial. EmailEngine provides a fourteen-day full trial, then costs $1,450 a year, excluding VAT, for production use.
Sources
We reviewed the linked product docs on October 23, 2026.